I think it would be cool to have a sign language option. Based on what little reading I've done about it, I think it would need to be an addition to existing languages so that in chargen you'd select Sign Language as your language, then say American as your regional modifier, then Black or Canadian or Southern as your accent/dialect.

All of them, as far as I can tell, just have one dialect and accent, since they're spoken by so few people. Also, I can understand if we don't want like a tenth of the languages in the game to be Native American languages when there are so few speakers, so I would at least push for Navajo to be in, since it has the most speakers out of all of them.